Storm passes but leaves flooded roads and avalanche danger behind in B.C.

Rainfall, wind, snow and winter storm warnings have been lifted for all of southernB.C.after a powerful system swept across the province leaving flooded or snow-clogged roads in its wake.

Torrential downpours forced flood watches or high streamflow advisories for several waterways on Vancouver Island onThursday. The deluge also prompted a boil water advisory for all users of the Comox Valley water system, including residents of Courtenay and Comox.

Severe rainfall caused turbidity levels at a back-up pump station to rise above acceptable thresholds, triggering the need for the boil water notice, theComoxValley Regional District saidin a news release.

Environment Canada says the two-day storm dropped as much as 100 millimetres of rain on Port Alberni and parts of eastern Vancouver Island equivalent to an entire month of rainfall while more than 50 millimetres fell Thursday at Vancouver International Airport.

In the mountains, Avalanche Canada says heavy snow has created a "high'' possibility of slides in the mountains of the South Coast and Vancouver Island, as well as through most of east central and southeasternB.C., meaning very dangerous avalanche conditions exist.

An "extreme'' avalanche ranking, which means natural and human-triggered avalanches are certain, remains posted for some regions along the Alberta/B.C. boundary, throughout Jasper National Park and in the alpine and treeline regions of Banff, Yoho and Kootenay national parks.